1. Field of the Invention
The subject invention relates to spas, whirlpools, and the like and, more particularly, to improvements in portable spas.
2. Description of Related Art
Portable spas are generally known in the prior art and have become increasingly popular as a source of relaxation and physical therapy. Their structure generally includes a spa shell or "tub" fabricated of various materials such as fiberglass/acrylic or various thermoplastics, a layer of thermal insulation placed against the shell, and a wooden support structure, often employing a 2.times.4 frame. In many cases, the exterior of the spa is a continuation of the shell. In some cases, decorative redwood patterns have been applied to serve as the exterior sidewalls or "skirts" of free-standing units. Decorative tile work has also been variously used in the interior and exterior design of portable spas.
Another known portable spa design employs a "soft core"--an inner annular core of "spongy" foam--together with a vinyl outer surface sewn to an inner vinyl liner much like a vinyl pool liner. The bottom of the spa is formed of a flat sheet of thin plastic cut, e.g., by scissors and stapled to the soft foam core. Because of its structure, the spa equipment, such as heaters and pumps, must be located remote from the spa.
In order to retain heat and reduce evaporation, portable spas have been fitted with insulating covers. The most commonly used cover is made of cut styrofoam halves surrounded by a sewn vinyl covering and permanently hinged together. This structure provides a flat cover, which is simply slid over the top of the spa when the spa is not in use. Another known spa cover for use with the "soft core" design is formed of one-piece polyethylene foam with a hand-sewn cover and fits into the spa like a cork. Other covers have employed foam cores with more resilient rigid covering materials and have employed various spring-biased hinged mechanisms for raising and lowering because of their considerable weight.
To meet industry safety standards such as ASTM F1346-91, spa covers must meet static load, deflection, and surface drainage standards. Under ASTM F1346-91, a spa cover must support a weight of 485 pounds. A deflection test must be met to ensure that if a child under five falls on the cover, he cannot slip through any openings. The surface drainage standard ensures that the cover will not retain enough water to risk drowning of a small child.
The prior art designs referenced above have a number of drawbacks. Exposed or partially protected bottom surfaces of many conventional spas are subject to attack by rodents and weather. While generally attractive, the decorative exterior of the spa is not always suited to the particular aesthetics of the moment. The conventional spa covers are labor intensive to manufacture, cumbersome to use, and have a notoriously short life span in the face of hot chlorinated water, sunlight, and the wear and tear of use. Many of the designs, such as the soft core "cork," cannot meet industry safety standards.